Argon is becoming increasingly more important for use in many industrial applications such as in the production of stainless steel, in the electronics industry, and in reactive metal production such as titanium processing.
Argon is generally produced by the cryogenic rectification of air. Air contains about 78 percent nitrogen, 21 percent oxygen and less than 1 percent argon. Because the argon concentration in air is relatively low, it is recovered as a co-product in conjunction with the recovery of the major air components. In order for argon recovery to be economical, the air separation plant must be of relatively large size, generally of a size of about at least 50 tons per day oxygen capacity. It would be desirable to have a cryogenic rectification system which can enable the economical recovery of argon from air separation plants of any size, particularly those having a capacity of less than 50 tons per day of oxygen.
Many air separation plants are built without the capability of producing argon because often there is initially a demand for oxygen or oxygen and some nitrogen without a corresponding demand for argon. When argon demand later develops, it may be difficult to retrofit the plant to produce argon and, thus, a new plant is built, often at a greater capacity, to replace the original plant and to produce argon. It would be desirable to have a cryogenic rectification system which can enable one to effectively recover argon processed in an air separation plant which does not have an argon column.
Accordingly, it is an object of this invention to provide a cryogenic rectification system which will enable one to effectively recover argon processed in a cryogenic air separation plant having a capacity which may be less than 50 tons per day of oxygen.
It is another object of this invention to provide a cryogenic rectification system which will enable one to effectively recover argon processed in a cryogenic rectification plant which does not have an argon column.